Austin Sigg attorneys question DNA evidence in Jessica Ridgeway case

By Karen Augéand Nic TuricianoThe Denver Post

Posted:
05/03/2013 08:33:29 AM MDT

Updated:
05/04/2013 01:11:55 AM MDT

FILE -- A student sits outside of the courtroom while visiting for a civics class before the hearing for Austin Sigg at the Jefferson County Courthouse on March 12, 2013. (AAron Ontiveroz, The Denver Post)

Austin Sigg, who turned 18 in jail, is charged with 18 counts related to Jessica's death, as well as an attack on a jogger at Ketner Lake last Memorial Day weekend.

Four of the counts carry mandatory life sentences.

Sigg pleaded not guilty last month, over objections of his attorneys, who said they needed more time to consider a plea. At that same hearing last month, Judge Stephen Munsinger set a Sept. 20 start date for Sigg's trial, which is expected to last three weeks.

He and his attorneys appeared in a Jefferson County courtroom Friday for a hearing on several pre-trial motions, most filed by Sigg's defense team.

The hearing revealed that the Colorado Bureau of Investigation issued three "contamination memos" regarding DNA testing in the Ridgeway and jogger cases, and signaled what may be a defense strategy: challenging the reliability of DNA evidence in the case.

Mitch Ahnstedt, one of Sigg's attorneys, said in court that the contamination memos "call into question the reliability of the work that's been done" on the case.

Prosecutors put a CBI lab director on the witness stand to explain the process of DNA testing and analysis.

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Kathleen Fetherston described the process, and brought with her some of the equipment used in DNA analysis.

She explained that sometimes — and the Memorial Day, 2012, assault is one of those times — DNA samples from more than one crime or suspected crime are placed in individual slots that are part of a single tray, and the testing is carried out on all the samples on that tray — known as a batch — at one time.

When DNA from the jogger's T-shirt was tested, contamination occurred on other samples on that tray, but the jogger-case DNA was not contaminated, Fetherston testified.

She was not asked about, and attorneys did not discuss, the two contamination memos that resulted from DNA testing in the Jessica Ridgeway case.

She did say, though, that samples from that case were not tested alongside samples from any other cases.

"Because of the public safety issues associated with this case, we were attempting to process samples as quickly as possible," she said.

Susan Medina, spokeswoman for CBI, said contamination memos aren't common at the agency.

"It is pretty rare that these contamination memos are created," she said, and they do not mean that a sample has been compromised or can no longer be used as evidence.

"They are done to ensure that we are transparent," with investigators and so that everyone involved in a case is aware of the situation

When an irregularity is detected scientist will notify a supervisor and they begin to investigate what happened, how to correct it and then retest the sample, Medina said.

Jessica was kidnapped on her way to school Oct. 5, 2012. Part of her body was found five days later in a field in Arvada.

At a preliminary hearing in February, Westminster police Detective Albert Stutson testified that Sigg told him over the phone, " 'I murdered Jessica Ridgeway. I have proof that I did it. You should send a squad car down here. I'll answer all the questions. I won't resist.' "

During Stutson's testimony, prosecutors played a tape of the phone call Sigg's mother, Mindy Sigg, made to police Oct. 23.

"My son wants to turn himself in for the Jessica Ridgeway murder. He just confessed to killing her," Mindy Sigg was heard saying.

When the dispatcher asked her what her son had told her, Mindy Sigg replied, "That he did it, and he gave me details."

The dispatcher told her she was doing the right thing, and she replied, "He did it. He's turning himself in."

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